Artificial lighting means.



Hl E. IVI-IS.l ARTIFICIAL LIGHTING MEANS. APPLICATION FILED FEB. 1a, 1913 Patented Mar. 17, 1914.

farm/5y UNITED sTATEs PATENT oEFIcE.

lHERBERT E. IVES, OF MOUNT `AIRY, PENNSYLVANIA, ASSIGNOR TO THE UNITED GAS IMPROVEMENT COIMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION i F PENNSYLVANIA.

ARTIFICIAL LIGHTING MEANS.

Specificationl of Letters Patent. i Patented M131- 175 1914h Application filed February 18, 1913. Serial No. 749,145.

To' all echo-m t may concern.' I

Be it known that I, HERBERT E. IvEs, a citizen of the United States, and a resident of Mount Airy, in the county of Philadelphia and State of Pennsylvania, have invented certain new anduseful Improvements in Articial Lighting Mea-ns, of which the following is a specification.

The principal object of the presentinvention is to provide a color filter or absorbing screen which operates`to modify artificial light passing through it so as to produce a resultant illumination equivalent to daylight, whereby many operations can be successfully carried on by artificial light which heretofore required daylight; for example, the matching of colors and certain surgical and other operations well vunderstood in the art.

The' `invention will-be claimed at 'the end hereof, but will be lirst described in connection with the accompanying drawings-form- A ing part hereof and in which I have illustrated certain embodiments, selected by me from other embodiments, for the sake of description.

In those drawings, Figure lis a transverse Isectional view of a color lter or absorbing screen embodying features of the invention.

Figs. 2 and 3 are similar views embodying modifications of the invention, and-Fig. 4, is

a diagrammatic view, hereinafter referred to for thesake of description.

Referring to the drawings and more particularly to Fig. 4, the rectangle 1 diagrammatically represents the spectrum of 'daylight; the letters indicate the colors of that spectrum. The height of the rectangle rep resents the intensity of the various colors as Vpresent in the spectrumv of daylight. The

curved line 2 indicates the relative intensity of the various colors in the spectrum of the artificial light which it is desiredto modify. For the sake of illustration and explanation the spectrum of the artificial light source and `the spectrum of the daylight source are drawn as of equal intensities at the extreme violet end. Artificial light sources as generically represented by the; area included under the curve 2 are usually different from daylight in possessing an excess of the longer spectrum wave len hs, that is yellow, orange and red. A11 absor ing screen or color filter in order to alter an artificial light spectrum to that of daylight must absorb these excessive radiatlons. If the relative intensities of the different colors of the spectrum are plotted upon such a scale that the intensities of daylight and the artificial light sources are the same at the blue extremity of the spectrum, then the transmission o f the absorbing screen must be as the reciprocal of the ratio at each color of the intensity of the articial' light spectrum to thedaylight spectrum. f

The color lter or absorbing screen embodying features of the present invention is adapted by absorption to produce the above 'described-result, or perhaps more accurately,

ai very close approximation to it. In Fig. 4 the approximation is indicated by the dotted line 3 'and the dotted lines 4, 5, 6, and 7, indicate the absorptions diagrammatic'ally and separately. For example, the dotted line 7 indicates that red rays are absorbed from the articiallight reducing it from the curve 2 to the line 7. Similarly the dotted lines 4, 5, and 6 represent other absorptions supplementary to the absorptions indicated by the line 7. Th dotted line 3 indicates the net result of the various absorptions as has been stated. p

A color filter or absorbing screen embodying features of the inventionlconsists of sections or elements. In all of the drawings the element `8 is of the color well known as signal green and may comprise glass of that color. Signal green is the trade-name for glass, 'which glass is colored usually with copper although occasionally by nickel or iron. The depth of color of the element 8,

or of the signal green glass,'may be initiallyV .the element 8 vwith an aqueous solution of copper sulfate and thereafter the solution of copper sulfate lor a like solution thereof will serve as a future comparison. The element 8 performs the function of absorbing the deep red rays from the artificial source as is' illustrated diagrammatically by the l-ine 7 in Fig. 3. Associated with the ele-r ment 8 are an additional element or elements of pink or purple color, which vperforms the light absorbing functions diagrammatically illustrated in Fig. 4, by lines 4, 5, and 6.

By purple or pink is meant that color or,

colors having the effect of absorbing the intermediate colors of the visible spectrum.

'The element 9 of purple or pink color is shown in Fig. l to ,comprise a lin as of gelatin, collodion or equivalent containing purple and pink dyes or pigments, preferably of fast color. The element 10 in Fig. 1 is of clear glass and When present serves -to protect the element 9. Y.

The construction and mode of operation in Figs. 2 and 3 is as has been described in connection with Fig. 1, except that in Fig. 2 the glass element l()a (or more, if desired,) may be colored so that jin connection with the element 9a the'requisitepurple orpink is produced and in Fig. 3, the pink or purple color is produced by a number of glass elements l1, which are of such individual colors as are a propriate for producingin combination t e p ink or purple color.

From the foregoing description it Will be Y evident-that the invention is not confined in modication in the proportion of the relaopen iame it is necessar to employ a larger f tive color constituents. For example, an openv gas iame gives rise to a larger proportion of red rays than do some other sources of artificial light, and in the case of such an proportion of the signa green color than 1s bach light.

It will be obvious to those skilled in the fications may be made in details of connot intend to limit my 'invention -in respect to-those matters nor in any Way further than the state of the prior art may require, but

Having thus described the nature and objects of my invention what I claim as new and desire to -secure by Letters Patent is:

l. A color filter or absorbing screen for the purposes described comprising the combination of superposed signal green and purple colors, substantially as described.

2. A color filter or 'absorbing screen for .the purpose described, comprising a signalgreen, glass elementwith other elements of purple color.

3. A color filter or absorbing screenl for the purposes described comprising the combination o f a signal green glass element with another superpos'ed element containing dyes v or pigments of purple color, substantially as described.

In testimony whereof: signed my name.

, 'HERBERT E. IVES.

l'VVitnesses: f j' S. .-E.'PM'1ERB0N,

I have hereunto required, for example, with a sdcalled Welsi I art to` which the invention relates that modistruction and varrangement and hence I do superposed 

